Process for breaking petroleum emulsions



Patented Dec. 10, 1935 v UNITED STATES PROCESS FOR BREAKING PETROLEUM EMULSIONS Melvin De Groote, St. Louis, and Bernhard Keiser, Webster Groves, Mo., assignors to Tretolite Company, Webster Groves, Mo., a corporation of Missouri No Drawing. Application December 31, 1934, Serial No. 760,030

8 Claims. (01. 19 -4) This invention relates to the treatment of emulsions of mineral oil and water, such as petroleum emulsions, for the purpose'of'separating the oil from the water.

Petroleum emulsions are of the water-in-oil type, and comprise fine droplets of naturally-occurring waters or brines, dispersed in a more or less permanent state throughout the oil which constitutes the continuous phase of the emulsion. They are obtained from producing wells and from the bottom of oil storage tanks, and are commonly referred to as "cut oil, "roily oil, emulsified oil and bottom settlings.

The object of our invention is to provide a'novel and inexpensive process for separating emulsions of the character referred to into their component parts of oil and water or brine.

Briefly described, our process consists in subjecting a petroleum emulsion of the water-in-oil type to the action of a treating agent or demulsifying agent of the kind hereinafter described, thereby causing the emulsions to break down and separate into its component parts of oil and water or brine, when the emulsion is permitted to remain in a quiescent state after treatment, or is subjected to other equivalent separatory procedures.

The treating agent or demulsifying agent used in our process consists of an oxy-hendecenoic acid material, and particularly a material of the kind in which an oxy-hendecenoic acid body has entered into an esterification reaction in the capacity of an alcohol. The most desirable reagents are those obtained by reaction of an hendecenoic acid body and a detergent-forming acid of the kind subsequently described, or else with a polybasic carboxy acid.

Hendecenoic acid is an unsaturated acid similar to certain fatty acids, but apparently not occurring naturally in any fat or oil. It is a lower homologue of oleic acid, and is obtained bydistilling ricinoleic acid or the glyceride thereof (castor oil) under diminished or atmospheric pressure. It is sometimes known as'undecylenic acid. The method of producing said acid is well known and is described in the publication Dictionary of Applied Chemistry, by Thorpe, 1922. In volume 4, pages 630 and 631 of the said publication the reaction of hendecenolc acid is indicated as follows:

but in the text the term hendecatoic acid" is erroneously used to refer to the product CnI-IzoOz. However, volume 3, page 515 of the said publication properly identifies hendecatoic acid as undecylic acid (0111-12202).

In producing the treating agent or demulsifying agent it is not necessary that the hendecenoic acid, which is employed as a raw material, be ab- 5 solutely pure, but it may be of a technical quality so as to contain some unconverted castor oil and certain products of decomposition other than hendecenoic acid. It may contain some cenanthol (heptoic aldehyde). This aldehyde can be re- 10 moved by blowing air or an inert gas through the commercial hendecenoic acid at a relativelylow temperature.

' In our co-pending application for patent Serial No. 760,024, filed. December 31, 1934, we have de- 15 scribed a process for breaking oil field emulsions by means of sulfonation products or sulfation products of certain unsaturated acid bodies derived by thermal or pyrolytic decomposition of unsaturated oxy fatty acid bodies, including, for 20 example, castor oil. The thermal or pyrolytic decomposition of castor oil yields hendecenoic acid, and the sulfation product of hendecenoic acid, followed by a hydrolytic washing process, may yield in part some oxyhendecenoic acid.

We have found that certain oil field emulsions are particularly susceptible to treatment with oxyhendecenoic acid bodies. This is particularly true of the esters in the form previously mentioned. In such instances, where the use of oxyhendec- 30 enoic acid bodies is indicated for demulsification, it is desirable to produce these materials by a process other than a sulfation process. Oxidation by air appears to be most feasible and at the same time inexpensive. It will further be pointed 35 out that there are herein described specific forms of oxyhendecenoic acid bodies, and particularly certain forms of esters previously mentioned, which do not appear to be present at all in the sulfohendecenoic acid body described as a demulsifying agent in our previously mentioned copending application for patent.

Hendecenoic acid of technical purity may be subjected to oxidation by any of the methods conventionally employed for oxidation of castor 45 oil, and the like. Our preference is to oxidize 'hendecenoic acid at relatively low temperature by means of moist air under pressure. We prefer to use a temperature of to C. and to use approximately 45 to '75 lbs. pressure. If desired, 50 hendecenoic acid may be oxidizedat a higher temperature by means of air or oxygen at atmospheric pressure.

We have referred to the product obtained by oxidizing hendecenoic acid 'as oxyhendecenoic 55 acid. The expression oxyhendecenoic acid" is intended to refer to the derivatives in which additional oxygen has been introduced into the molecules. For instance, this may be in the manner indicated by the formula CuHzoOa. This represents the saturation of the ethylene linkage by means of an atom of oxygen. It {is believed that oxidation, especially with mo t air, results in the conversion of this added oxygen atom into two hydroxyl radicals, so that ultimately one apparently obtains dihydroxyhendecatoic acid, as indicated by the formula C11H2c(OH)2Oz. In other words, the addition product of hendecenoic acid is the substitution product, at least hypothetically, of hendecatoic acid.

It appears immaterial whether an oxygen atom is introduced or two hydroxyl radicals are introduced. This is perfectly evident, in view of esterification reactions in which the oxyhendecenoic acid is acting as a dihydric alcohol. For example, if one considers a reaction with a dibasic acid, such as phthalic acid, it is immaterial whether the two carboxyls react with two hydroxyl radicals, thus causing the elimination of two molecules of water, or if the two carboxyls react with an atom of oxygen in an ether type structure with the elimination of only one molecule of water. This is comparable to esterification involving an acid anhydride, such as acetic anhydride, or phthalic anhydride instead of the corresponding acid. However, the reactions involving a monobasic acid, such as oleic acid, acetic acid, or ricinoleic acid, appear to be predicated most simply on the existence of the alcoholiform hydroxyl radical. In any event, the presence of the hydroxyl radical is proven by the acetyl value, and it is desired to point out that it is immaterial as to the final form of the oxidized hendecenoic acid body. As herein used, the expression oxyhendecenoic acid body is intended to broadly cover both types of materials, and the expression "hydroxylated hendecenoic acid body is employed to indicate the hydroxylated type, although strictly speaking, from the standpoint of the most widely accepted nomenclature, this product might better be termed hydroxy or dihydroxy hendecatoic acid. We are not employing such nomenclature in every instance, simply in order to avoid confusion.

After producing such oxyhendecenoic acid bodies, as previously explained, they may be used in the acid condition or neutralized with any suitable base, so as to produce an ammonium salt, a sodium salt, potassium salt, calcium salt, magnesium salt, etc., or they may be esterified with any suitable alcohol, such as ethyl alcohol, methyl alcohol, etc., so as to produce an ester. Such oxyhendecenoic acids may be combined with basic amines, such as triethanolamine.

However, we have found that the most effective reagents of this type and the ones which we prefer to use as a demulsifying agent in practising out invention, are the species derived from oxyhendecenoic acid by reactions involving the oxyhendecenoic acid body acting as an alcohol, and in certain instances, as a dihydric alcohol. It is well known, of course, that ricinoleic acid or hydroxystearic acid may act as an alcohol, as well as an acid. Similarly, dihydroxystearic acid may act as an alcohol, as well as an acid, and as indicated by its name, may act as a dihydric alcohol. We prefer to react oxyhendecenoic acid or its salt or ester with acids such as acetic, etc.

similar to the reagents disclosed in the previously 5 and particularly with various long chain monocarboxy acids, particularly the type of acid, which, when combined with caustic soda, yields detergent-like materials. For instance, it is well known that the ordinary fatty acids, such as 5 oleic acid, stearic acid, ricinoleic acid, etc. combine with'alkali, such as caustic soda, to yield soaps. It is also true that certain petroleum acids, such as naphthenic acids, combine with alkalies to yield soap-like materials. The same 10 is true of abietic acid derived from resin. These three classes of materials are often referred to as detergent-forming long chain monocarboxy acids. In order to prepare some of the most desirable reagents to be employed in the present 15 process, we prefer to react oxyhendecenoic acid or its salts or esters with such detergent-forming acids, so as to produce an ester in which the oxyhendecenoic acid has acted as an alcohol. If desired, two moles of hendecenoic acid may be 0 heated, so as to yield an ester acid, i. e., poly oxyhendecenoic acid. Various materials acidic in nature and obtained by oxidation of fatty acids or fatty oils may be employed for the same purpose. It is immaterial as to the particular 25 detergentacid or fatty acid or fatty bond united with the oxyhendecenoic acid, provided that it is a relatively long chain mono-carboxy acid of the type which combines with caustic soda or the like to give detergent-like materials. Diricinoleic acid may be employed. Polyricinoleic acid may be employed, etc.

In forming esters from oxyhendecenoic bodies in such a manner that the hendecenoic body acts as an alcohol, one finds that a subspecies of this type, which is also very effective for use in the present process, is obtained by reactions involving dibasic carboxy acids, such as phthalic acid, oxalic acid, maleic acid, succinic acid, fumaric acid, citric, adipic, sebacic, tartaric, glu- 40 taric, diphenic, naphthalenic, etc. Reference is made to U. S. Patent No. 1,976,602, to De Groote, Adams and Keiser, dated October 9. 1934. This patent describes the manufacture of various reagents, intended for demulsification, from castor oil or similar hydroxylated acid bodies, in which the hydroxylated acid acts as an alcohol by virtue of the alcoholiform hydroxyl and an ester is produced by reaction with at least one of' the dibasic carboxy acids previously mentioned. 50 Similarly, reference is made to U. S. Patent No. 1,977,146, to Roberts, dated October 16, 1934. In this last mentioned patent there are described reagents for breaking oil field emulsions which are described De Groote et a1. patent, except that in the Roberts patent the dibasic carboxy acids are additionally esterified with polyhydric alcohols, such as glycerol, to give "a resin type structure. It is perfectly obvious that oxyhendecenoic bodies 60 may be caused to enter esterification reactions of the kind described in both of the above mentioned patents, in respect to castor oil or ricinoleic acid bodies. In other words, the oxyhendecenoic acid body acts in an analogous manner 65 to ricinoleic acid or castor oil. We have found this particular type of reaction to yield the most effective demulsifying agent for use in the present process. In order to summarize what has been said previously, one may consider hendec- 7 enoic acid as being CmHisCOOH. The hendecenoic acid residue C1oH19 may be designated for sake of convenience as T, and thus the acid may be considered as T.COOH, and the oxy acid may be considered as Y.T.COOH, wherein Y is at least one oxygen atom, or at least, one hydroxyl radical, CO0 is a conventional carboxyl residue, and T.C0O is the hendecenoic acid radical. Y.T.COOH is an alcoholic type acid in the same sense that ricinoleic acid is an alcoholic a id.

er, is an se of Y.T.COQH may be converted into a salt or and thus be written Y.T.COOZ, in which acidic hydrogen or its equivalent in the a salt or ester.

Similarly, reactions of the oxy acid may inv lve Y, as previously stated, forming compoun s of the type R.T.COOZ, whereinR is an acid residue.

Thus, the expression oxyhendecenoic acid material refers to compounds of the type Y.T.COOZ, or the type R.T.COOZ, and in both instances, are characterized by the presence of the hendecenoic acid residue T.

Those reactions which involve Y.T.COOH acting as an acid means that the acidic hydrogen H will be replaced by a metallic atom or by an organic radical, and of 'course, will be contemplated by the formula, Y.T.COOZ, as previously described.

In regard to those reactions in which Y.T.COO

" acts as an alcohol, Y is replaced by an acid resilowing manner: Hendecenoic acid of technical purity is cautiously oxidized so as to yield dihydroxy hendecatoic acid. Approximately 296 lbs. of phthalic anhydride are mixed with 92 lbs. of glycerol and heated for approximately ten to fifteen minutes at to C. until a thin, clear water-white liquid resin intermediate, free from any unreacted phthalic anhydride, has been produced. This product is characterized by having a free carboxylic radical available for further esterification. To this liquid resin intermediate, free from unreacted phthalic anhydride, there is added 218 lbs. dihydroxy hendecatoic acid and the mixture is heated from approximately 150 to 250 C. for approximately 10 to 30 minutes, after which it is permitted to cool and is diluted with 10 to 50% by weight of denatured alcohol. The compound is then ready for use, and any free carboxylic hydrogen remaining may be neutralized by the addition of triethanolamine.

The use of demulsifying agents consisting of various carboxy acids or compounds having more than one carboxyl group, is well known in the treatment of water-in-oil emulsions. In the use of conventional demulsifying agents it is the common practice to-use them not only in the form of acids, but also in the form of salts or esters, or half salts, or half esters, or ester salts, in case of dibasic acids. Where such reagents have both a carboxylic hydrogen and a sulfonic hydrogen, it is well known that only the sulfonic hydrogen need be neutralized, if desired. The salts generally employed are the sodium salt, potassium salt, ammonium salt, calcium, magnesium, the triethanolamine. salt, etc. The esters may be employed, such as the methyl ester, ethyl ester, propyl ester, butyl ester, amyl ester, hexyl ester, octyl ester, etc. Aromatic or cyclic esters may be employed. What has been said in regard to the use of conventional demulsifying agents applies such, or after dilution with, any suitable solvent, 5

such as water, petroleum hydrocarbons, such as gasoline, kerosene, stove oil, a coal tar product, such as benzene, toluene, xylene, tar acidoil, cresol, anthracene oil, etc. Alcohols, particularly aliphatic alcohols, such as methyl alcohol, ethyl l0 alcohol, denatured alcohol, propyl alcohol, butyl alcohol, hexyl alcohol, octyl alcohol, etc. may be employed as diluents. Miscellaneous solvents,- such as pine oil, carbon tetrachloride, sulfur dioxide extract obtained ln the refining of petroleum, etc. may be employed as diluents. Similarly, the material or materials employed as the demulsifying agent of our process may be admixed with one or more of the solvents customarily used in connection with conventional dem'ulsifying 20 agents. Moreover, said material or materials may be used alone or in admixture'with othersuitable well known classes of demulsifying agents. such as demulsifying agents of the modified fatty acid type, the petroleum sulfonate type, the alkylated 25 sulfo-aromatic type, etc.

It is well known that conventional demulsifying agents may be used in a water-soluble form, or in an oil-soluble form, or in a form exhibiting both oil and water-solubility. Sometimes they may be used in a. form which exhibits relatively limited water-solubility and relatively limited oil-solubility. However, since such reagents are sometimes used in'a ratio of 1 to 10,000, or 1 to 20,000; or 1 to 30,000, such an apparent insolubility in oil and water is not significant, because said reagents undoubtedly have solubility within the concentration employed. This same fact is true in regard to the material or materials employed as the demulsifying agent of our process.

As stated previously, it has been so common to use a conventional demulsifying agent derived from an acid in the form of the acid itself, or in the form of a salt, or in the form of an ester, that the expression acid body is frequently em- 45 ployed to mean the acid itself, or an ester thereof, or a salt thereof. The word body" is herein employed in this same sense in conformity with its prior usage in the trade, and particularly in various patents, of the prior art,and also to in- 50' elude esters obtained by the oxyhendecenoic acid material acting in the capacity of an alcohol.

It is to be noted that the present invention is concerned with the breaking of oil field emulsions by means of a reagent characterized by the pres- 55 once of an oxyhendecenoic acid residue. In certain cases this residue may be specifically an hydroxy or dihydroxy hendecatoic acid residue. oxyhendecenoic acid bodies are characterized, as stated, by the presence of an oxyhendecenoic acid 60 radical or rasidue. These bodies consist of either the acid itself or its derivatives. The words hendecenoic acid body" are used in the sense that contemplates both the acid itself and its derivatives. The derivatives of oxyhendecenoic acid 65 are of two'kinds, i. e., the type in which oxyhendecenoic acid acts as an acid to form a salt or simple ester, and secondly, the type in which oxyhendecenoic acid acts as an alcohol to form a more complex ester. Of course, the .acid may 70 also act in a dual capacity. This last mentioned species in which oxyhendecenoic acid acts as an alcohol, may be divided into numerous subspecies. The two most valuable subspecies for use as a reagent in breaking oil field emulsions 75 consists of the types in which oxyhendecenoic acid has acted as an alcohol in combination with a monohydroxy, detergent-forming acid of the kind described, or where oxyhendecenoic acid has acted as an alcohol in combination with polybasic carboxy acids of the kind described. It is understood that in a general manner the reagents may be used in the form of acid, salts or esters, or any convenient form.

In practising our invention a treating agent or demulsifying agent of the kind above described is brought into contact with or caused to act upon the emulsion to be treated, in any of the various ways or by any of the various apparatus now generally used to resolve or break petroleum emulsions with a chemical reagent.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A process for breaking a petroleum emulsion of the water-in-oil type,which consists in subjecting the emulsion to the action of a demulsifying agent comprising an oxyhendecenoic acid material, of the formula type X.T.COO.Z, wherein X is at least one oxygen atom, or at least one hydroxyl radical, or an acid residue, T is a hendecenoic acid residue, CO is a conventional carboxyl residue, and Z is an acidic hydrogen equivalent.

2. A process for breaking a petroleum emulsion of the water-in-oil type, which consists in subjecting the emulsion to the action of a demulsifying agent obtained by a reaction involving an oxyhendecenoic acid body acting as an alcohol, of the formula type X.T.COO.Z, wherein X is an acid residue, T is a hendecenoic acid residue, CO0 is a conventional carboxyl residue, and Z is an acidic hydrogen equivalent.

3. A process for breaking a petroleum emulsion of the water-in-oil type, which consists in subjecting the emulsion to the action of a demulsifying agent obtained by a reaction between a detergent-forming, monocarboxy acid and an oxyhendecenoic acid body acting as an alcohol.

4. A process for breaking a petroleum emulsion of the water-in-oil type, which consists in sub- 5 jecting the emulsion to the action of a demulsifying agent obtained by reaction between a ricinoleic acid body and an oxyhendecenoic acid body acting as an alcohol.

5. A process for breaking a petroleum emulsion of the water-in-oil type, which consists in subjecting the emulsion to the action of a demulsifying agent comprising a product obtained by reaction between a polybasic carboxy acid and an oxyhendecenoic acid body acting as an alcohol.

6. A process for breaking a petroleum emulsion of the water-in-oil type, which consists in subjecting the emulsion to the action of a demulsifying agent comprising a product obtained by partial esterification of a polybasic carboxy acid with apolyhydric alcohol and subsequent esterification of the residual carboxylic hydrogen with an oxyhendecenoic acid body acting as an alcohol.

7. A process for breaking a petroleum emulsion of the water-in-oil type. which consists in subjecting the emulsion to the action of a demulsifying agent comprising a product obtained by reaction between an acidic glycerol phthalic anhydride resin intermediate and an oxyhende'cenoic acid body.

8. A process for breaking a petroleum emulsion of the water-in-oil type, which consists in subjecting the emulsion to the action of a demulsifying agent comprising a product obtained by reacting 92 lbs. of glycerol with 296 lbs. phthalic anhydride so as to yield a clear, acidic resin intermediate, and followed by reaction with 218' lbs. dihydroxyhendecenoic acid and then followed by subsequent dilution with denatured alcohol.

' MELVIN DE GROO'I'E. 40

BERNHARD KEISER. 

